Today’s leading asset managers are constantly self-evaluating their investment decisions by performing comprehensive analysis of their performance. Attribution analysis, also referred to as return attribution or performance attribution, is a valuable tool for evaluating a portfolio’s performance in comparison to a specific benchmark, asset segment, sector, or security. Whether investments performed well or poorly, asset managers want as much detail as possible about what worked, what did not, and why. Much can be learned by analyzing investment approaches that either outperform or lag against benchmarks and their peer groups to determine what decisions paid off in order to fine-tune an investment strategy and to better understand past performance.